Arabinogalactan obtained from the tree Larix occidentalis has a high affinity for a receptor found in hepatocytes termed the asialoglycoprotein receptor [Groman, E. V., P. M. Enriquez, et al. (1994). "Arabinogalactan for hepatic drug delivery."Bioconjugate Chemistry in press, incorporated herein by reference]. Materials attached to arabinogalactan are concentrated in hepatocytes after injection, including diagnostic agents like superparamagnetic iron oxide [Josephson, L., E. V. Groman, et al. (1990), "A functionalized superparamagnetic iron oxide colloid as a receptor directed MR contrast agent." Mag Reson Imag 8(5): 637-46; Reimer, P., R. Weissleder, et al. (1990). "Receptor imaging: application to MR imaging of liver cancer." Radiology 177(3): 729-34 both incorporated herein by reference), and therapeutic agents like the antiviral agent araAMP. Thus, arabinogalactan is useful as carrier of agents to hepatocytes in targeted drug delivery. Such applications require a highly purified, endotoxin free grade of arabinogalactan, which is the object of the current invention.